The present invention relates generally to surgical instruments for ligating body tissue structures and particularly, ligating instruments for use in least invasive surgical procedures. More specifically, the present invention relates to surgical clip appliers having movable jaws and means for holding a tissue structure in tension while a clip is applied to the structure.
In least invasive surgical (LIS) procedures, such as endoscopy, laparoscopy, pelviscopy, thoracoscopy and arthroscopy, elongated instruments of small cross-section are introduced into a body cavity through a small incision or a specialized cannula such as a trocar sleeve. Visualization is facilitated through the use of endoscopes, laparoscopes, arthroscopes and the like which have a video lens secured to a shaft for manipulation and which are connected to a video monitor viewed by the surgeon. In this way, various surgical procedures may be performed without the need for the large incisions of conventional open surgical techniques, thereby minimizing patient trauma, decreasing recovery time and reducing the risk of infection.
During LIS procedures, it is frequently necessary to ligate tissue structures such as ducts, blood vessels and the like. Such ligation is commonly accomplished using a ligation instrument specifically designed for introduction through the small incisions or cannulas used in LIS procedures. Frequently, a surgical clip applier will be used to apply U-shaped surgical clips to a tissue structure. Surgical clip appliers designed for least invasive surgical procedures such as endoscopy and laparoscopy typically have an elongated shaft with an interior axial passage, a clip closure mechanism at the distal end of the shaft, and a handle and actuator secured to the proximal end of the shaft. Desirably, such clip appliers will be capable of storing multiple clips within the shaft which are automatically fed to the closure mechanism at the distal end. In this way, the clip applier may be positioned through an incision or cannula and used to apply multiple clips within a body cavity without the necessity of removing the device to reload clips. Examples of such surgical clip appliers are seen in U.S. Pat. No. 5,084,057, U.S. Pat. No. 5,163,945 and U.S. Pat. No. 5,192,288, the complete disclosures of which are incorporated herein by reference.
Surgical clip appliers like the aforementioned generally are designed to apply surgical clips in one of two ways. In a first type of clip applier, exemplified in U.S. Pat. No. 5,163,945 ('945) or U.S. Pat. No. 5,084,057 ('057), a pair of movable jaws are mounted at the distal end of the shaft. The jaws point in a distal direction and surgical clips are fed into the jaws with the clip legs also pointing in the distal direction. Using clip appliers of this type a tissue structure is ligated by introducing the shaft into the body cavity, positioning the tissue structure between the jaws, and closing the jaws so that the clip legs are closed tightly on the structure.
In a second type of surgical clip applier, exemplified in U.S. Pat. No. 5,192,288 ('288), a stationary anvil at the distal end of the shaft provides a forming surface against which a slidable hammer moves so as to close a clip against the forming surface. Advantageously, the forming surface of the anvil is disposed at a non-zero angle, typically 90.degree., relative to the axial direction, so that clips are applied with the clip legs pointing in a lateral direction. Such a configuration may be advantageous for ligating tissue structures disposed in positions which are unaccessible using distally-pointing jaws. In addition, a laterally-oriented anvil provides a hook-like element for engaging the tissue structure, whereby a proximal force may be exerted on the clip applier to hold the tissue structure in tension. This allows the tissue structure to be positioned away from surrounding organs or other tissue, eliminating the risk of clipping unwanted areas, as well as improving visualization of the tissue structure to be ligated.
While surgical clip appliers designed for lateral application of clips as described in the '288 patent are advantageous in some situations, in certain procedures a surgeon may desire to apply a clip to a duct or vessel disposed in such a position that a clip applier having distally-pointing jaws as in the '945 or '057 patents will be more effective. However, using a clip applier with distally-pointing jaws, the tissue structure to be ligated will tend to be deflected away from the surgeon as the jaws are positioned around the structure so as to seat the structure against the apex of the clip. The structure may be pushed up against nearby organs or other tissue, which may be engaged in the clip if the clip is closed. Further, the tissue structure may be pushed into a position where it is obscured from view by the laparoscope or other visualization device.
For these and other reasons, an improved surgical clip applier for LIS procedures is desired which has distally-oriented jaws for applying clips with legs pointing in a distal direction, but which also has the tissue holding and tensioning capabilities of laterally-oriented closure mechanisms. The clip applier will preferably facilitate engagement, tensioning and retention of a tissue structure in a fixed position relative to the shaft of the device, so that it remains in a fixed position as the clip is applied. In this way, once the surgeon has tensioned and positioned the tissue structure as desired, the application of the clip to the structure will not change its position, which might result in overtensioning the tissue structure or interfering with unwanted organs or other tissue. Desirably, the clip applier will be introducible through a 10 mm trocar sleeve or other cannula so as to be useful in laparoscopic surgical procedures. Preferably, the clip applier will support the tissue structure on two opposing sides of the jaws to facilitate uniform tensioning and balanced support on either side of the point of ligation. Further, the clip applier should allow the tissue structure to be engaged, tensioned and ligated using a minimal number of actuators, preferably by means of a single actuator.